Move 27: Instead of this move, white could capture a large chunk of stones. How?

Move 45: Instead of backing down and capturing some stones so quickly, white can continue to rip black's shape. How?

Move 48 and 50: Good moves. Connecting your formerly break-able shapes into a solid central wall is a great choice.

Move 68: Good move. White could have played here to break your shape, so preventing this is good.

Move 74: Instead of P19, what other stone can black capture, and how?

Move 83: White's move allowed black to win the fight in the corner. But white can win it with a different move. How?

Move 98: Not needed. If white cuts at M7, how can black capture it?

Move 130: Good, you saw the ladder.

Move 138: Not needed. If white cuts here, how can black capture it?

Move 140: Not needed. If white gets a second move and cuts at E9, how can black respond?

Move 170: Not needed. If white plays at H11, how can black capture it?

Move 204: Black can capture a medium sized chunk of stones. How?

Move 212: Almost. What's a better move?

Move 238/239: Still squeezing the toothpaste and obtaining ripped shape.

Final exercise: Go over your game yourself again and find at least a few other instances where you (or your opponent!) squeezed the toothpaste and/or ended up with broken/ripped shape. And if you can, in each case you find, spend some time to identify alternative moves that could have avoided that result.

Hope this helps. Good luck on your games!

Move 27: Instead of this move, white could capture a large chunk of stones. How?

Mmm...well, White could play O7, forcing Black to connect at P6, and then Q7 would kill the black stones.

Okay, but what if black plays Q7 instead of P6? You're on the right track, but try looking at the shape again.

..If Black plays Q7 instead of P6 then I guess it escapes and is happy, right? I don't really see anything White could do about this...

Maybe something like P10, which would probably make Black play P11, so then White could play O8 followed by Black blocking at N8, and then White making an atari at O10, making Black connect at N9...and then White could do whatever he wanted with the group he had. Something like that, I'm not really sure though.

Oh, White could play at R19, forcing Black to connect at P19, and then White could make two eyes with S19. Now White is able to kill off Black's S16 group.

Oh, by playing at M8 which would kill off the stone because it would've been a ladder that White could not win.

Try looking at the position just a move or two earlier. Try to find a better play than white's O7.

Right idea, but wrong move. If white plays R19, black plays S19. Then when white captures at P19, it's only a ko fight. Instead, white should play S19 to begin with. Then white has two eyes immediately because black playing at R19 would be self-atari.

And for the questions for moves 74, 138, 140, 170, 204, 212 - all correct, very good.
You are clearly capable of seeing most of these things yourself if you look for them, so you just have to look for them in your games. Check frequently for simple tactics you might otherwise miss, and make sure each time you defend that it's actually necessary.

6: You voluntarily walk into the hane at the head of two stones. This make your opponent's stone at Q4 a perfect play for him. ( It is slightly out of sequence, but the end result is the same. ) See http://senseis.xmp.net/?HaneAtTheHeadOfTwoStones
Far better for you would be R7.

In a more general sense, you will do best in a fight if the fight does not progress toward your opponent's nearby stones.

10+12: Again, you are forcing him to make strong moves. The result here cannot end well for you.

16: What does this stone do for you? O2 is dead, and white connects over its dead body. If O2 were alive, then this would be useful.

20: Again, forcing your opponent to make strong moves. Consider this: as general rule, you want to be able to separate your opponent's stones, right? So, therefore, he wants to play O5. And you are forcing him to do it.

24+26: This is known as 'toothpaste go'.

30: A good move! You have lost a lot, but this consolidates the survivors.

gotta go...maybe more later

Joaz, could you explain your comment about move #6 in further detail? I understand that this move does hit the head of his two stones, thus violating the well-known proverb of avoiding the hane at the head of your stones, but this move seems very similar to the basic moves of the avalanche joseki, except that the player's corner stone is on the 4-4 point rather than the 3-4 point of the typical avalanche joseki sequences. As a beginner, I'm just confused as to what makes it a bad move in this case.

txcpa, very good question. Here's a short (and very incomplete) reply:
As you pointed out, there's a well-known proverb for it, and the proverb exists
because sometimes (in many cases), but not always, the proverb is correct.
The avalanche is an exception to the proverb (among other exceptions).
So one can view your question from another angle: yes, is bad because the proverb applies here (for all the usual reasons; see Sensei's, for example);
so the real mystery is why is the avalanche an exception? A short answer is that for the situation specific to the avalanche,
research has shown that B and W can play that way (exception to the proverb), leading possibly to very complex variations.
For a more detailed analysis of the avalanche, please see other resources.

Two important differences:
(1) although it may appear "very similar" to the avalanche, the 4-4 versus the 3-4 here makes the situation completely different;
(2) moreover, there is an existing W stone at O3 ( ).

...the OP was not playing the joseki correctly, since ...his corner stone on the 3-4 point, as opposed to the 4-4 point (in addition to the presence of the other white stone at O3).

You might want to compare it to a replay of a high level game. A quite different view. Thin clouds arise here and there. The sun is still shining through.

txcpa, correct. As you're probably aware by now, Go is super specific -- even one stone can sometimes make a huge difference...

It looks like you have received a lot of good advice.

Here's one that's a bit more obvious: Take your time before making a move. Try to consider at least two possibilities. You spent less than 20 minutes on all of your moves combined. It's okay to lose on time. It is easier to review and learn from a game if you put some thought into each move. It allows you to review not just the moves that were played but the way you had thought about the move. A lot of beginners will often say that "Oh, why did I play that move" or "I lost because of obvious reading mistakes". It is good that they recognize their own mistakes, but significant growth comes from analyzing mistakes that the player himself cannot recognize. If a player's game is not cluttered with mistakes that he already knows are mistakes, it is easier for that player to seek advice about improving. Part of this process is playing slowly so that we don't make mistakes below our level.

I bet you will improve quickly. People who ask for reviews of their games seem to get strong faster than those who do not.

Lamb, thanks for posting the game. I find it very useful to read comments from other DDK games.

In my goviewer I can replay your game at high speed. It reminds me of my computer drawing a fractal. You might want to compare it to a replay of a high level game. A quite different view. Thin clouds arise here and there. The sun is still shining through.
In detail you notice that for example from move 8 to move 80 both of you play only contact moves ( except for two diagonals moves ), always close to the previous opponent move. Glueing everything tightly together. Like knitting a pullover.
Sometimes it happens to me as well. It must be wrong because better players play different.